The invention concerns a method for the closed-loop control of an internal combustion engine-generator unit.
An internal combustion engine provided as a generator drive is usually delivered by the manufacturer to the end customer without the coupling and generator. The coupling and generator are installed at the end customer's facility. To guarantee a constant rated frequency for the current supply into the power supply system, the internal combustion engine is operated in a closed-loop speed control system. In this regard, the speed of the crankshaft is detected as a controlled value and compared with a set speed, i.e., the reference input. The resulting control deviation is converted by a speed controller to a correcting variable for the internal combustion engine, for example, a set injection quantity.
Since certain data on the coupling characteristics and the moment of inertia of the generator are often unavailable to the manufacturer before the delivery of the internal combustion engine, the electronic control unit is often delivered with a robust set of controller parameters, the so-called standard set of parameters.
A speed run-up ramp or a run-up ramping rate is stored in this standard set of parameters for the starting process. To allow the fastest possible run-up, this parameter is set to a large value, e.g., 550 revolutions/(minute×second). The previously described closed-loop speed control system and a speed run-up ramp are known, for example, from DE 101 22 517 C1 of the present applicant.
In the case of a generator with a large moment of inertia, a large deviation can develop between the set run-up ramp and the actual run-up ramp. This control deviation of the actual speed from the set speed causes a significant increase in the set injection quantity. In a diesel engine with a common-rail injection system, the significant increase in the set injection quantity promotes the formation of black smoke. The significant increase in the set injection quantity also causes incorrect computation of the injection start and the set rail pressure, since both of these values are computed from the set injection quantity.
For the manufacturer of the internal combustion engine, the problems described above mean that for an internal combustion engine-generator unit with a large moment of inertia, an on-site service technician must adapt the control parameters of the standard set of parameters to the specific conditions. This is time-consuming and expensive.